Canister lets you add water (or bodily fluids) to recharge batteries

Adding water (or even urine) to a new cartridge, SiGNa's mobile-H2™, produces …

SiGNa Chemistry Inc. is launching a hydrogen-producing cartridge, the mobile-H2™, that will work with a portable, pocket-sized fuel cell charger to provide instant power for cell phones and other mobile devices. You simply add water to the cartridge, and the device will charge depleted batteries on the go. For further convenience, any water will do (even waste water). Unlike solar battery chargers, you don’t need to worry about getting enough sunlight. According to its press materials, these cartridges provide a steady level of power from beginning to end.

This sounds a bit like magic, but it actually involves some well-known chemistry. SiGNa’s hydrogen cartridge technology is based on the combination of sodium and silicon in the form of sodium silicide (NaSi). Normally, sodium metal reacts violently with water to produce hydrogen gas. SiGNa has found a technique to take full advantage of the reducing power of sodium without the safety concerns.

SiGNa hasn’t released details on the synthesis of their sodium silicide. However, based on publications from SiGNa’s CEO and collaborators, we know that, in the past, they have absorbed sodium into silica by coating commercially available silica gel with a liquid sodium-potassium alloy (Na2K) to create a black powder. They then give the powder various heat treatments to create a material with enhanced stability.

SiGNa’s sodium silicide might have a similar production process. NaSi is stable for long periods in open air (over two years) and reacts controllably with water.

When SiGNa’s sodium silicide meets water, it immediately produces low-pressure hydrogen gas (H2). Then, a low-cost fuel cell device, such as myFC’s Powertrekk, converts the H2 gas into electricity to recharge batteries. The other products of this reaction are simply heat and sodium silicate (Na2Si2O5), which is a common compound that is used in cements, textiles, automobiles, and other materials. The heat released can be recaptured and used within the electricity-making process, so we assume that this won’t amount to a super hot device that’ll be uncomfortable to carry around.

The charging device.

While devices like the Powertrekk are portable for extended trips away from a power grid, they might not be more convenient than just carrying around more charged batteries. First, you would need to buy a fuel cell charger like the Powertrekk, which has yet to be priced. Second, you would need to bring a supply of cartridges with you.

The fuel cell devices are reusable, but the hydrogen-producing cartridges are not. Cartridges have to be replaced once the active sodium silicide is used up. Lithium batteries, on the other hand, are reusable. In some ways, you’re trading the inconvenience of carrying multiple batteries for carrying a bunch of mobile-H2™ cartridges. To figure out if this tradeoff is worthwhile economically and environmentally, we spoke with Michael Lefenfeld, SiGNa’s CEO.

Ars Technica: Can you tell us a bit about the mobile-H2? When will it be available?

Michael Lefenfeld: Our most recent release is a small 5 watt hour canister that we’re now launching in conjunction with the Powertrekk device by myFC. It should be available at the end of summer and the beginning of fall.

Ars: How much will the cartridges and the myFC device cost?

Lefenfeld: The price of the cartridges hasn’t been released yet because we’re still going into the large ramp up of large scale manufacturing. Obviously 5 watt hours is about the same energy as 4 AA batteries, so we’re going to need to come in cheaper than that, but we don’t have the price for it, yet. The myFC price is also not determined, yet.

Ars: Are the cartridges recyclable? What happens to them when they’re done?

Lefenfeld: They are recyclable. The byproduct of the reaction is the material known as sodium silicate, the main ingredient in toothpaste and also used in glass manufacturing and cement. The stuff is found in the ground pretty regularly. There are no toxic metals, and there are no heavy metals used in our process. Everything is based on aluminum and pretty much our chemicals. It’s not toxic and can be thrown away in municipal waste. There’s also a program that we’re trying to get into place, but probably won’t be ready right away—it’s for the exchange of these canisters, because all the parts are reusable.

Ars: What’s the advantage over just buying a lot of batteries and having them charged and ready? I can reuse lithium batteries. What’s the advantage of these cartridges, which you have to replace? You also have to buy a myFC Powertrekk, and how long will that device last?

Lefenfeld: The Powertrekk device will last a very long time. It’s literally an electric engine. There’s no reason for it to degrade unless you run over it or something. So that’s not a worry.

The price point of the cartridges is, in a way, so much more competitive than buying a lot of batteries. Recharging batteries even in the developed world is difficult. Think of it when you’re in the airport, and everybody is searching for that one outlet to charge their cell phone or whatever. This allows you to be off that grid in a very competitive fashion. We estimate that at the largest of scales, we can be probably 10 times cheaper per watt hour than AA batteries.

Ars: I’m reading that overall, the reaction yields 9.5 percent of H2 gas by weight of water added. The DOE, for example, has a 9 percent goal, but that’s for the total weight. Do you have a percent yield for the total weight?

Lefenfeld: It’s 9.8 percent by weight of water. Plus, the DOE’s goal is for automotives, so we don’t deal with that. For our most advanced system with just pure sodium silicide and all the weight in water, we’re looking at somewhere on the order of five and change.

Ars: In your JACS papers, like the 2005 JACS communications, there are descriptions of producing material where you have sodium absorbed into silica. Is the reaction for the cartridge material something similar?

Lefenfeld: Not exactly. [In] that paper that you’re looking at there is more for our structural chemicals, where they’re absorbed in nanostructure systems and the electrons are delocalized, etc. This is more of a compound, so it’s a sodium silicide. Na and Si are equimolar. It’s a 5 electron shift. Silicon has more electron movements; sodium has 1, so that’s why you get such a high amount of hydrogen out.

But like the other materials in the JACS papers, sodium silicide production involves a similar platform process, like getting rid of the oxidation issues. It’s similar in features, but not the synthesis processes.

Ars: Does the efficiency decrease with different water?

Lefenfeld: No. We have programs with the military that are using urine. In some of the markets that we’re looking into, like in some of the emerging markets, potable water is a very scarce resource. We pride ourselves in not taking away one resource to provide another. We want to minimally take away drinking water. Electricity is great, but you need water to survive.

Ars: What do you see in the future for these cartridges? Can you expand this to vehicles, or will that require a complete redesign?

Lefenfeld: Small vehicles, not cars. Bikes, scooter, golf carts, those types of things. We’re not looking at this as an energy replacement for gasoline.

Overall, SiGNa's mobile-H2™ have potential, especially in developing nations, where there are limited access to electric outlets. The ability to use impure water, even urine, with the cartridges is an advantage as well. However, without knowing the price of the fuel-cell chargers and the cartridges, we cannot comment on their economic viability. If the recycling program that Lefenfeld mentioned can be set up, the cartridges would be even a better option for people who need portable battery chargers.

Latest Ars Video >

The Greatest Leap, Episode 3: Triumph

In honor of the 50th anniversary of the beginning of the Apollo Program, Ars Technica brings you an in depth look at the Apollo missions through the eyes of the participants.

The Greatest Leap, Episode 3: Triumph

The Greatest Leap, Episode 3: Triumph

In honor of the 50th anniversary of the beginning of the Apollo Program, Ars Technica brings you an in depth look at the Apollo missions through the eyes of the participants.

Yun Xie
Yun Xie / Yun Xie is a contributing science writer at Ars, where she covers the latest advancements in science and technology for Ars. She currently works in scientific communications, policy, and review. Emailreenxie@gmail.com//Twitter@yun_xie

45 Reader Comments

YAY, so I can carry a recharger that not only requires water, but these disposable cartridges, which generates power quite slowly, and for which just carrying spare battery packs is more convenient and cheaper? Love new technology....

The device surely works, but the active element is NaSi, not water. Yes, the hydrogen atoms come from water - but the energy is really stored in the NaSi. See how quiet they were re: the price of cartridges? You cannot beat the second law of thermydynamics - NaSi has to be synethesized somehow, and that takes a nontrivial amount of energy, and you'll be paying for that energy by paying for the cartridges. And sure enough, with all the chemical conversions of stuff along the way this will be pricier than paying for the energy the old-fashioned way.

Calling the addition of water "recharging" is a gross misnomer. Water is not the source of charge here; NaSi is.

If it passed 5VDC over a USB port, I'd buy one as soon as it was available. This would be perfect for camping, to keep a couple electronic luxuries charged. I've standardized on AAs for all my replaceable-battery gear, and as long as I do a bit of bookkeeping before heading out, I only have to carry a couple spares. But devices with non-standard batteries (cell phone, Zune, e-reader) are a difficulty.

NiMH, and to a lesser extent LiIon, batteries have a significant problem with self-discharge over time. This will have a significant use in situations where you want a power source that can be relied upon to provide energy in a few month's or a year's time.

NiMH, and to a lesser extent LiIon, batteries have a significant problem with self-discharge over time. This will have a significant use in situations where you want a power source that can be relied upon to provide energy in a few month's or a year's time.

That was my first thought as to "benefits over batteries" - it sounds like the shelf life on a sealed cartridge will be essentially infinite.

NiMH, and to a lesser extent LiIon, batteries have a significant problem with self-discharge over time. This will have a significant use in situations where you want a power source that can be relied upon to provide energy in a few month's or a year's time.

This.

Perfect for tucking away in a disaster or power outage kit, and no doubt an instant hit for survivalists.

The device surely works, but the active element is NaSi, not water. Yes, the hydrogen atoms come from water - but the energy is really stored in the NaSi. See how quiet they were re: the price of cartridges? You cannot beat the second law of thermydynamics - NaSi has to be synethesized somehow, and that takes a nontrivial amount of energy, and you'll be paying for that energy by paying for the cartridges. And sure enough, with all the chemical conversions of stuff along the way this will be pricier than paying for the energy the old-fashioned way.

Calling the addition of water "recharging" is a gross misnomer. Water is not the source of charge here; NaSi is.

That's what I was wondering. I mean, how much potential energy is stored in NaSi, anyways? Most of our reduction batteries already have about as much chemical power as one can expect, is this really an advantage over them? I mean, let's assume that there is, since the whole point of the research is that NaSi is new and hard to produce, which, as you point out, means it all comes down to cost of manufacture.

It'd actually be worse if the power were from the water, since water would be split into H2 and O2, then recombined into water in the hydrogen fuels cell... you'd bump up against conservation laws there.

NiMH, and to a lesser extent LiIon, batteries have a significant problem with self-discharge over time. This will have a significant use in situations where you want a power source that can be relied upon to provide energy in a few month's or a year's time.

Not that it's bad, but I'm having a hard time thinking of any real world application where I would want an energy source that needs to be ready in a year's time yet requires water to use. Sure rechargeables aren't good at this, but non-rechargeables are just fine.

There's no way in hell this will be cost competitive. Sure, at large scale, it might well be. But short of government intervention, there's just no way they'll get to those scales. Things might be different if the energy density was exceedingly high, e.g. if one cartridge would recharge an AA battery dozens of times, or even your laptop once.

The device surely works, but the active element is NaSi, not water. Yes, the hydrogen atoms come from water - but the energy is really stored in the NaSi. See how quiet they were re: the price of cartridges? You cannot beat the second law of thermydynamics - NaSi has to be synethesized somehow, and that takes a nontrivial amount of energy, and you'll be paying for that energy by paying for the cartridges. And sure enough, with all the chemical conversions of stuff along the way this will be pricier than paying for the energy the old-fashioned way.

Where exactly did they say water was the active element? Also, they clearly state:

So technically the H2 gas is the energy producing agent, not the NaSi or water. Unless Ars has been misinformed, you may want to read the article again.

bozox wrote:

Calling the addition of water "recharging" is a gross misnomer. Water is not the source of charge here; NaSi is.

I think you may have misunderstood the what they were saying, may need to work on your reading comprehension. When they talk about "recharging" it is strictly about the batteries in whichever device you are plugging into them. They are not referring to the fuel cell charger, keyword "CHARGER". Despite what people may think this is not a battery because it is not storing energy but producing it on the fly. There is a big difference especially when it comes to shelf life.

The device surely works, but the active element is NaSi, not water. Yes, the hydrogen atoms come from water - but the energy is really stored in the NaSi. See how quiet they were re: the price of cartridges? You cannot beat the second law of thermydynamics - NaSi has to be synethesized somehow, and that takes a nontrivial amount of energy, and you'll be paying for that energy by paying for the cartridges. And sure enough, with all the chemical conversions of stuff along the way this will be pricier than paying for the energy the old-fashioned way.

Where exactly did they say water was the active element? Also, they clearly state:

So technically the H2 gas is the energy producing agent, not the NaSi or water. Unless Ars has been misinformed, you may want to read the article again.

Here's the thing: it takes energy to split water into H2 and O2. That energy has to come from somewhere, and it obviously doesn't come from the water. So if water spontaneously splits upon contact with NaSi, then the energy must be coming from the NaSi.

If there's some way to bulk produce the sodium silicide from renewable power (e.g., a solar-thermal driven chemical processing plant?), then this could offer a municipal installation that recycles waste water, co-generates DC power, and spits out glass beads for downstream production of concrete / GRP.

Here's the thing: it takes energy to split water into H2 and O2. That energy has to come from somewhere, and it obviously doesn't come from the water. So if water spontaneously splits upon contact with NaSi, then the energy must be coming from the NaSi.

I never said NaSi didn't provide the energy to split H2 and O2. I was referring to the chemical that was actually providing the charge for the batteries. And according to this article, they are using the H2 to produce that charge. The whole NaSi reaction with water is just there to produce the H2 in a safe and convenient manner. So again, people need to work on their reading comprehension.

That price per watt seems like it would only shake out if you used every watt produced. Add water to the cart, matters go afoot, and the reaction continues until the NaSi is spent. Does the charger itself contain any kind of secondary storage?

Being a cheapskate, I imagine scrambling around finding things to charge so's not to waste my precious H2.

Ars: What’s the advantage over just buying a lot of batteries and having them charged and ready? ...

Lefenfeld: ... Think of it when you’re in the airport, and everybody is searching for that one outlet to charge their cell phone or whatever. This allows you to be off that grid in a very competitive fashion.

I can take these sealed metal canisters of chemicals through airport security? Do they have to be in a 1 quart ziploc bag?

That price per watt seems like it would only shake out if you used every watt produced. Add water to the cart, matters go afoot, and the reaction continues until the NaSi is spent. Does the charger itself contain any kind of secondary storage?

Being a cheapskate, I imagine scrambling around finding things to charge so's not to waste my precious H2.

You make a good point. I would imagine there would be some mechanism that controls the flow of water.

Ars: What’s the advantage over just buying a lot of batteries and having them charged and ready? ...

Lefenfeld: ... Think of it when you’re in the airport, and everybody is searching for that one outlet to charge their cell phone or whatever. This allows you to be off that grid in a very competitive fashion.

I can take these sealed metal canisters of chemicals through airport security? Do they have to be in a 1 quart ziploc bag?

The label on the cannister in the photo says that it's not safe to transport on an aircraft, so I suspect that you'll not be able to take them through security until that gets changed (should it ever; the problems with transporting gas generators in aircraft are many).

Ars: What’s the advantage over just buying a lot of batteries and having them charged and ready? ...

Lefenfeld: ... Think of it when you’re in the airport, and everybody is searching for that one outlet to charge their cell phone or whatever. This allows you to be off that grid in a very competitive fashion.

I can take these sealed metal canisters of chemicals through airport security? Do they have to be in a 1 quart ziploc bag?

Check the fine print on the canister label in the photo at the top.

NOT suitable for aircraft carry on.

You'll need to put them in your checked luggage.

........

For those who do not see a need for a "battery" that has years of shelf life, consider the logistics of keeping all your NiMh, NiCAD, Li-Ion batteries maintained so they are ready the day the power goes out and you require an emergency recharge on your portable equipment (radios make nice paperweights). Much easier to go to the closet, pull out a canister and add some rainwater, pond water, mud puddle water etc.

The definition of emergency includes the fact that you don't have advance notice of the schedule, that's the 'emerge' part of the word

Depending on the weight of these chargers and cartridges...this would be a good thing for hikers.As someone who has hiked the Appalachian Trail more than a few times and once all the way from Maine to Georgia, If the weight is lighter than spare batteries for a emergencyradio/emergency nav system. I would pay a good amount of $$ for it

I was thinking about electric motors you could hook up to bikes. I guess if you could build a battery small enough to power a regular motorized bicycle/dirt bike to travel say 100-150km (dare I say farther?) there'd be a huge market for something like this in developing countries, or even for students here in North America. Hell, I'd even sell my car because I only work some 25km from my office, and take the bus in the winter. People might even start collecting rain water just to stock up for fuel.

Here's the thing: it takes energy to split water into H2 and O2. That energy has to come from somewhere, and it obviously doesn't come from the water. So if water spontaneously splits upon contact with NaSi, then the energy must be coming from the NaSi.

I never said NaSi didn't provide the energy to split H2 and O2. I was referring to the chemical that was actually providing the charge for the batteries. And according to this article, they are using the H2 to produce that charge. The whole NaSi reaction with water is just there to produce the H2 in a safe and convenient manner. So again, people need to work on their reading comprehension.

OK, I'm clearly not understanding the point you're trying to make.

H2O goes in. It interacts with NaSi, gaining sufficient energy to split into H2 and O2. The NaSi is consumed. The H2 is harvested and run through a fuel cell, where it is oxidized (using atmospheric O2) via a catalytic reaction within a fuel cell, yielding water, heat, electricity, and Na2Si2O5. The fuel cell is not consumed.

So water goes in, water comes out. The fuel cell remains (essentially) unchanged. The only consumed input is NaSi, which means the only energy input must be NaSi. Which means energy was expended manufacturing the NaSi, making the NaSi the energy storage mechanism.

The bulk of the cost (financial, energy expenditure) in manufacturing batteries - primary or rechargeable - is represented in the materials in the battery, not its usable energy content. If this company has a process that's similarly cheap relative to manufacturing the AA cells they're making a comparison to, perhaps they can be competitive.

The inherent inefficiencies in liberating hydrogen from water only to combust it later are known. At a very small scale such as a cellphone or laptop, it's of little concern that the hydrogen fuel cycle might take 4 watt-hours to produce a single watt-hour of useful output. Once you get into any significant amount of energy (or energy consumption represents an appreciable percentage of the device's cost-of-ownership), hydrogen's inherent inefficiencies become a potentially show-stopping concern.

Li-ion and hybrid NiMH have fairly low self-discharge rates (month-to-month, it's somewhat comparable to the alkalines of several years ago). Not as good as lithium primary cells, but also reusable.

It looks like a great early model of something that could in a few years revolutionize the way we view portable power. The real value in something like this lies down the road when our technology to obtain hydrogen from water becomes much more efficient. Think of this as the Atari of mobile power generation...

As for the powertrekk http://www.powertrekk.com/product/ it seems to have a battery built in. So once the process have been started the battery will be charged, and then any device attached (via USB-A btw) will be charged from that.

It looks like a great early model of something that could in a few years revolutionize the way we view portable power. The real value in something like this lies down the road when our technology to obtain hydrogen from water becomes much more efficient. Think of this as the Atari of mobile power generation...

The problem with freeing hydrogen from water is that it will always take more energy to liberate the hydrogen from water using perfectly-efficient hydrolysis, hydrocarbon reformation, or any other technology than you can possibly extract from it via combustion or a hydrogen fuel cell, again at perfect efficiency.

5 Watt-hour is nowhere near 4xAA's. A good NiMH cell like GP's Recyko delivers 1.2V x 2.1Ah, or 2.52 Wh, even with high current devices like digital cameras. They are doomed if a big puck deliver just the power of two AA's, as that thing looks way larger than the size of the equivalent in batteries. And it's debatable if a cell would be any cheaper as well, as those low self discharge NiMH's are going for $1.60 each on Amazon right now.

It'd be interesting to see if they could sell kit to recondition cardidges at home. Then it is revolutionary because you're producing portable energy source at home perhaps using a solar panel etc and you take BP and the governments out of the loop as they can't tax your fuel. I'd pay good money for such freedom.

While devices like the Powertrekk are portable for extended trips away from a power grid, they might not be more convenient than just carrying around more charged batteries

That's assuming you would only use this in place of a charger for a cell phone or laptop or similar device.

This would be great for emergency situations or situations (like say in the field in places with extremely limited electricity sources, a la third-world scenarios) where direct electricity is not a option.

I think it's brilliant. I'm excited to see people run with this tech and see how creatively it can be applied.